<?php

/**
 * @package php-font-lib
 * @link    http://php-font-lib.googlecode.com/
 * @author  Fabien M�nager <fabien.menager@gmail.com>
 * @license http://www.gnu.org/copyleft/lesser.html GNU Lesser General Public License
 * @version $Id: font_truetype_collection.cls.php 34 2011-10-23 13:53:25Z fabien.menager $
 */
require_once dirname(__FILE__) . "/font_binary_stream.cls.php";
require_once dirname(__FILE__) . "/font_truetype.cls.php";

/**
 * TrueType collection font file.
 * 
 * @package php-font-lib
 */
class Font_TrueType_Collection extends Font_Binary_Stream implements Iterator, Countable {

    /**
     * Current iterator position.
     * 
     * @var integer
     */
    private $position = 0;
    protected $collectionOffsets = array();
    protected $collection = array();
    protected $version;
    protected $numFonts;

    function parse() {
        if (isset($this->numFonts)) {
            return;
        }

        $tag = $this->read(4);

        $this->version = $this->readFixed();
        $this->numFonts = $this->readUInt32();

        for ($i = 0; $i < $this->numFonts; $i++) {
            $this->collectionOffsets[] = $this->readUInt32();
        }
    }

    /**
     * @param int $fontId
     * @return Font_TrueType
     */
    function getFont($fontId) {
        $this->parse();

        if (!isset($this->collectionOffsets[$fontId])) {
            throw new OutOfBoundsException();
        }

        if (isset($this->collection[$fontId])) {
            return $this->collection[$fontId];
        }

        $font = new Font_TrueType();
        $font->f = $this->f;
        $font->setTableOffset($this->collectionOffsets[$fontId]);

        return $this->collection[$fontId] = $font;
    }

    function current() {
        return $this->getFont($this->position);
    }

    function key() {
        return $this->position;
    }

    function next() {
        return ++$this->position;
    }

    function rewind() {
        $this->position = 0;
    }

    function valid() {
        $this->parse();
        return isset($this->collectionOffsets[$this->position]);
    }

    function count() {
        $this->parse();
        return $this->numFonts;
    }

}
